The **magic constant** or **magic sum** of a magic square is the sum of numbers in any row, column, or diagonal of the magic square. For example, the magic square shown below has a magic constant of 15. In general where is the side length of the square.

For normal magic squares of orders *n* = 3, 4, 5, 6, 7, and 8, the magic constants are, respectively: 15, 34, 65, 111, 175, and 260 (sequence A006003 in the OEIS). For example, a normal 8x8 square will always equate to 260 for each row, column, or diagonal.

The term **magic constant** or **magic sum** is similarly applied to other "magic" figures such as magic stars and magic cubes. Number shapes on a triangular grid divided into equal polyiamond areas containing equal sums give polyiamond magic constant.^{ [1] }

The magic constant of an *n*-pointed normal magic star is .

In 2013 Dirk Kinnaes found the magic series polytope. The number of unique sequences that form the magic constant is now known up to .^{ [2] }

In the mass model, the value in each cell specifies the mass for that cell.^{ [3] } This model has two notable properties. First it demonstrates the balanced nature of all magic squares. If such a model is suspended from the central cell the structure balances. ( consider the magic sums of the rows/columns .. equal mass at an equal distance balance). The second property that can be calculated is the moment of inertia. Summing the individual moments of inertia ( distance squared from the center x the cell value) gives the moment of inertia for the magic square. "This is the only property of magic squares, aside from the line sums, which is solely dependent on the order of the square."^{ [4] }

In physics, a **force** is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol **F**.

**Radius of gyration** or **gyradius** of a body about an axis of rotation is defined as the radial distance to a point which would have a moment of inertia the same as the body's actual distribution of mass, if the total mass of the body were concentrated there.

In recreational mathematics, a square array of numbers, usually positive integers, is called a **magic square** if the sums of the numbers in each row, each column, and both main diagonals are the same. The **order** of the magic square is the number of integers along one side (*n*), and the constant sum is called the **magic constant**. If the array includes just the positive integers , the magic square is said to be **normal**. Some authors take magic square to mean normal magic square.

In mathematics, particularly in linear algebra, **matrix multiplication** is a binary operation that produces a matrix from two matrices. For matrix multiplication, the number of columns in the first matrix must be equal to the number of rows in the second matrix. The resulting matrix, known as the **matrix product**, has the number of rows of the first and the number of columns of the second matrix. The product of matrices **A** and **B** is denoted as **AB**.

The **moment of inertia**, otherwise known as the **mass moment of inertia**, **angular mass**, or most accurately, **rotational inertia**, of a rigid body is a quantity that determines the torque needed for a desired angular acceleration about a rotational axis, akin to how mass determines the force needed for a desired acceleration. It depends on the body's mass distribution and the axis chosen, with larger moments requiring more torque to change the body's rate of rotation.

In mathematics, a **square matrix** is a matrix with the same number of rows and columns. An *n*-by-*n* matrix is known as a square matrix of order . Any two square matrices of the same order can be added and multiplied.

In linear algebra, a **diagonal matrix** is a matrix in which the entries outside the main diagonal are all zero; the term usually refers to square matrices. An example of a 2×2 diagonal matrix is , while an example of a 3×3 diagonal matrix is. An identity matrix of any size, or any multiple of it, is a diagonal matrix.

In mathematics, a **Hermitian matrix** is a complex square matrix that is equal to its own conjugate transpose—that is, the element in the i-th row and j-th column is equal to the complex conjugate of the element in the j-th row and i-th column, for all indices i and j:

In mathematics, a **magic cube** is the 3-dimensional equivalent of a magic square, that is, a number of integers arranged in a *n* × *n* × *n* pattern such that the sums of the numbers on each row, on each column, on each pillar and on each of the four main space diagonals are equal to the same number, the so-called magic constant of the cube, denoted *M*_{3}(*n*). It can be shown that if a magic cube consists of the numbers 1, 2, ..., *n*^{3}, then it has magic constant

In mathematics, a **perfect magic cube** is a magic cube in which not only the columns, rows, pillars, and main space diagonals, but also the cross section diagonals sum up to the cube's magic constant.

In mathematics, a ** P-multimagic square** is a magic square that remains magic even if all its numbers are replaced by their

A **pandiagonal magic square** or **panmagic square** is a magic square with the additional property that the broken diagonals, i.e. the diagonals that wrap round at the edges of the square, also add up to the magic constant.

A **most-perfect magic square** of doubly even order *n* = 4*k* is a pan-diagonal magic square containing the numbers 1 to *n*^{2} with three additional properties:

- Each 2×2 subsquare, including wrap-round, sums to
*s*/*k*, where*s*=*n*(*n*^{2}+ 1)/2 is the magic sum. - All pairs of integers distant
*n*/2 along any diagonal are complementary.

**Sylvester's law of inertia** is a theorem in matrix algebra about certain properties of the coefficient matrix of a real quadratic form that remain invariant under a change of basis. Namely, if *A* is the symmetric matrix that defines the quadratic form, and *S* is any invertible matrix such that *D* = *SAS*^{T} is diagonal, then the number of negative elements in the diagonal of *D* is always the same, for all such *S*; and the same goes for the number of positive elements.

A **magic series** is a set of distinct positive numbers which add up to the magic constant of a magic square and a magic cube, thus potentially making up lines in magic tesseracts.

A **magic graph** is a graph whose edges are labelled by positive integers, so that the sum over the edges incident with any vertex is the same, independent of the choice of vertex; or it is a graph that has such a labelling. If the integers are the first *q* positive integers, where *q* is the number of edges, the graph and the labelling are called **supermagic**.

**Correspondence analysis** (**CA**) or **reciprocal averaging** is a multivariate statistical technique proposed by Herman Otto Hartley (Hirschfeld) and later developed by Jean-Paul Benzécri. It is conceptually similar to principal component analysis, but applies to categorical rather than continuous data. In a similar manner to principal component analysis, it provides a means of displaying or summarising a set of data in two-dimensional graphical form. Its aim is to display in a biplot any structure hidden in the multivariate setting of the data table. As such it is a technique from the field of multivariate ordination. Since the variant of CA described here can by applied either with a focus on the rows or on the columns it should in fact be called **simple (symmetric) correspondence analysis**.

In mathematics, a **matrix** is a rectangular *array* or *table* of numbers, symbols, or expressions, arranged in *rows* and *columns*. For example, the dimension of the matrix below is 2 × 3, because there are two rows and three columns:

**Water retention on mathematical surfaces** is the catching of water in ponds on a surface of cells of various heights on a regular array such as a square lattice, where water is rained down on every cell in the system. The boundaries of the system are open and allow water to flow out. Water will be trapped in ponds, and eventually all ponds will fill to their maximum height, with any additional water flowing over spillways and out the boundaries of the system. The problem is to find the amount of water trapped or retained for a given surface. This has been studied extensively for two mathematical surfaces: magic squares and random surfaces. The model can also be applied to the triangular grid.

In mathematics, the **(2,1)-Pascal triangle** is a triangular array.

- ↑ http://oeis.org/A303295/
- ↑ Walter Trump http://www.trump.de/magic-squares/
- ↑ Heinz http://www.magic-squares.net/ms-models.htm#A 3 dimensional magic square/
- ↑ Peterson http://www.sciencenews.org/view/generic/id/7485/description/Magic_Square_Physics/

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